Composite abrasive bodies

ABSTRACT

Composite abrasive bodies, which include abrasive product supports, abrasive particles and cured adhesives bonding the abrasive product supports and the abrasive products, are provided. The cured adhesives may be two-component polyurethane or (meth)acrylate adhesives. In addition, methods for preparing the composite abrasive bodies are also provided.

This is a Division of Application No. application Ser. No. 11/896,573,filed Sept. 4, 2007, which is a Continuation of application Ser. No.10/580,531, filed May 25, 2006, which is a National Phase ofPCT/EP2004/053097 filed Nov. 25, 2004, which claims priority to EuropeanPatent Application No. 03027086.2 filed Nov. 25, 2003. The disclosure ofthe prior applications is hereby incorporated by reference herein intheir entirety.

BACKGROUND

1. Technical Field

This disclosure relates to fabrication of composite abrasive bodies.

2. Prior Art

Abrasive products have been used for a long time for machiningmaterials. Abrasive products consist of, inter alia, abradant granularparticles that are fixed to a backing material by means of a binder.

DE 198 53 550 C1 describes an abrasive flap disc in which abrasivegrains are dispersed on a base bonding coat that is applied to abacking.

U.S. Pat. No. 5,722,881 describes use of epoxies for bonding abrasiveflaps to an abrasive wheel.

Epoxy adhesives have the disadvantage that they either have very longcuring times or must be cured by heat. As a result, long holding timesand/or high energy costs for curing are required for efficient massproduction, which means increased costs for the production process.

SUMMARY

Therefore, an aim of the present disclosure is to provide compositeabrasive bodies that can be produced in a way that avoids thedisadvantages of the prior art.

This disclosure provides novel composite abrasive bodies, as well asmethods for their preparation and use.

The novel composite abrasive bodies of embodiments may overcome thedisadvantages of the prior art by the use of a two-componentpolyurethane or (meth)acrylate adhesive. Two-component polyurethane or(meth)acrylate adhesives cure extremely rapidly and in particular enablerapid bonding even at room temperature. This enables fast working timesand energy-saving industrial mass production of these composite abrasivebodies.

These and other features and advantages of various embodiments ofmaterials, devices, systems and/or methods are described in or areapparent from, the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the composite abrasive bodies and methods ofpreparing and using composite abrasive bodies are explained in moredetail below with the help of the drawings. The same reference numbersare assigned to the same elements in the different figures. Forcedirections are indicated by arrows. These figures are intended to beillustrative and non-limiting; thus, only those elements essential fordirect understanding of the disclosed composite abrasive bodies andmethods for preparing and using composite abrasive bodies are shown.

FIGS. 1 a-c) are partial schematic cross sectional views through anembodiment of an abrasive product support/abrasive product/adhesiveassembly of this disclosure. In particular:

FIG. 1 a) is a partial cross sectional view showing an abrasive productbonded to an abrasive product support along a longitudinal surface,

FIG. 1 b) is a partial cross sectional view showing an abrasive productbonded to an abrasive product support along a transverse edge, and

FIG. 1 c) is a partial cross sectional view showing a possible designfor an embodiment of an abrasive product;

FIG. 2 is a schematic view of an abrasive flap disc of an embodiment ofthe disclosure.

FIG. 3 is a partial schematic cross sectional view of the abrasive flapdisc shown in FIG. 2, taken along the line AA.

FIG. 4 is a schematic view of a grinding machine with abrasive flap discof an embodiment of the disclosure.

FIG. 5 is a schematic view of an abrasive flap wheel of an embodiment ofthe disclosure.

FIG. 6 is a partial schematic cross sectional view of the abrasive flapwheel shown in FIG. 5, taken along the line BB.

FIG. 7 is a schematic view of a grinding machine with abrasive flapwheel of an embodiment of the disclosure.

FIGS. 8 a) and b) are partial schematic cross sectional views through acomposite abrasive body to illustrate its fabrication. In particular:

FIG. 8 a) is a partial schematic cross sectional view showing acomposite abrasive body including inserted abrasive products, and

FIG. 8 b) is a partial schematic cross sectional view showing acomposite abrasive body in which the abrasive products have been tilted.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure relates, in exemplary embodiments, to a compositeabrasive body including at least one abrasive product support, at leastone abrasive product, as well as at least one cured two-componentpolyurethane or (meth)acrylate adhesive bonding the abrasive productsupport and the abrasive product to each other. Abrasive particles mayalso be present on the surface of the abrasive product.

Herein, the term “(meth)acrylate” refers to acrylic acid esters andmethacrylic acid esters.

The present disclosure also relates, in exemplary embodiments, to theuse of a two-component (meth)acrylate adhesive in the fabrication ofcomposite abrasive bodies. The two-component (meth)acrylate adhesiveincludes a first component that contains at least one (meth)acrylatemonomer and a second component that contains at least one radicalinitiator. The two-component (meth)acrylate adhesive may be used to bondthe abrasive product support and the abrasive product together.

The present disclosure also relates, in exemplary embodiments, to theuse of a two-component polyurethane adhesive in the fabrication ofcomposite abrasive antibodies. The two-component polyurethane adhesiveincludes a first component that contains at least one polyamine or onepolyol and a second component that contains at least one polyisocyanate.The two-component polyurethane adhesive may be used to bond the abrasiveproduct support and the abrasive product together.

In addition, the present disclosure relates, in exemplary embodiments,to methods for fabricating composite abrasive bodies. These methodsinclude mixing of the two components of a two-component polyurethane or(meth)acrylate adhesive, applying the mixed adhesive to the abrasiveproduct support, bringing the mixed adhesive into contact with at leastone abrasive product, and curing the adhesive.

FIGS. 1 a-b) are partial schematic cross sectional views of a compositeabrasive body according to exemplary embodiments. The illustratedcomposite abrasive body comprises an abrasive product support 1 that isbonded to an abrasive product 2 by means of a two-component(meth)acrylate or polyurethane adhesive 4. The abrasive product may bebonded along the large-area surface (FIG. 1 a) or at or around itstransverse edge (FIG. 1 b).

Abrasive particles may be present on the surface of abrasive product.Abrasive particles for use in embodiments may be made from materialssuch as are known to the person skilled in the art in this field. Forexample, abrasive particles may be prepared from natural or syntheticmaterials such as emery, garnet, flint, quartz, corundum, potassiumfluoroborate, cryolite, chiolite, diamond, silicon carbide, cubic boronnitride (CBN), or the like. It is additionally known that such particlesmay be present in different grain sizes and grain shapes. The personskilled in the art may select suitable material or materials in therespectively suitable grain size or mix of grain sizes in therespectively optimal grain shape, depending on the specific grindingproblem. The abrasive product of embodiments may have these abrasiveparticles present over the entire surface or only in certain areas.However, in particular embodiments, the abrasive particles may bepresent only on one side of the abrasive product, such as in FIG. 1 c.

In some embodiments, the abrasive product may be in the form of aflap-shaped abrasive member.

The abrasive product, or the flap-shaped abrasive member, of embodimentsmay be designed in very different ways. In some embodiments, theabrasive product may consist of a rigid material and abrasive particles,for example, as can be fabricated by a casting or sintering process frommetal, duromers or reactive resins, optionally by dispersing abrasiveparticles on the rigid material or by rolling abrasive particles intothe rigid material.

In other embodiments, the abrasive product may be constructed from atleast one cloth or paper 101, at least one binder 102, as well asabrasive particles 3, as shown schematically in FIG. 1 c). In suchembodiments, the cloth may be a crossply or knit fabric. Fibers used forthe cloth in exemplary embodiments may include carbon, glass, nylon,aramid, cotton, and polyester fibers, as well as mixtures thereof.

Various polymeric synthetic resins may be used as a binder for embeddingthe abrasive particles in the cloth or paper material. For example,suitable binders include the reaction products based on polyepoxides,poly(meth)acrylates, or polyurethanes, as well as binders based onphenol—formaldehyde resins or polyimides and two-component(meth)acrylate or polyurethane adhesives, such as those used to bind theabrasive product to the abrasive product support, and the unfilledreactive components on which these two-component (meth)acrylate orpolyurethane adhesives are based.

In embodiments in which the abrasive product includes a cloth, crossply,or knit fabric, the binder can penetrate between the fibers, and maycompletely surround the cloth, crossply, or knit fabric, and the bindermay not be present on only one side of the cloth, crossply, or knitfabric, as shown in FIG. 1 c. The abrasive particles may also besurrounded by cloth, crossply, or knit fabric or their fibers, and notonly by the binder.

In certain embodiments, the abrasive particles may be embedded in thebinder, i.e., partially surrounded by binder, where part of the surfaceof the abrasive particles is free.

In addition to the binder, optionally a size coat may also be used inembodiments. Such a size coat may be applied over the binder, forexample, to protect the binder from outside influences.

The abrasive product support may play the role of a carrier for abrasiveproducts in embodiments. The abrasive product support, in exemplaryembodiments, may be connected to a machine, such as by clamping forces,so that the abrasive product contacts the material to be abraded bymeans of rotary or shearing motions, and thus the material removaloperation is accomplished.

The abrasive product support of exemplary embodiments may be made eitherfrom a rigid material, such as metal or duromer plastics, or from anelastic material. Elastic materials may be easily adjusted to fit thecontours of the workpieces to be abraded, and thus are suitable for finegrinding operations or for workpieces with complex surface geometries.However, elastic abrasive product supports may have lower mechanicalload bearing capacities as well as reduced lifetimes.

Rigid materials may be used in some embodiments as abrasive productsupports and have higher mechanical load bearing capacity than elasticmaterials. However, rigid materials are difficult to use for grindingoperations on workpieces that have mostly non-planar surfaces.

Abrasive product support of exemplary embodiments may be a circulardisc, a wheel, or a belt. In some embodiments, the abrasive product isbonded to the abrasive product support on the largest area surface ofthe disc or wheel or belt, such as in the radial direction of the discor wheel.

In some embodiments, the abrasive product may be bonded to the abrasiveproduct support on the peripheral surface of the wheel or circular disc,such as in a radial orientation.

The adhesive used to bond the abrasive product support and the abrasiveproduct in embodiments may be a two-component polyurethane or(meth)acrylate adhesive. The adhesive reacts very fast even at roomtemperature. However, the adhesive may also be cured at highertemperatures. The adhesive may be cured, in particular embodiments, at atemperature between 10° C. and 180° C., such as between 20° C. and 80°C., between 20° C. and 40° C., or at room temperature. However, inparticular for the two-component (meth)acrylate adhesive, it isadvisable for safety reasons to use higher temperatures duringapplication and curing.

In embodiments in which the adhesive is a two-component (meth)acrylateadhesive, the first component includes at least one (meth)acrylatemonomer. Monofunctional, difunctional, trifunctional, tetrafunctional,and pentafunctional (meth)acrylate monomers are suitable. Particularlysuitable (meth)acrylate monomers include methyl methacrylate, isobornyl(meth)acrylate, cyclohexyl (meth)acrylate, t-butyl (meth)acrylate,tetrahydrofurfuryl (meth)acrylate, dicyclopentadienyl (meth)acrylate,dicyclopentadienyloxyethyl (meth)acrylate, ethylene glycoldi(meth)acrylate, di-, tri-, tetraethylene glycol di(meth)acrylate,propylene glycol di(meth)acrylate, di-, tri-, tetrapropylene glycoldi(meth)acrylate, butanediol di(meth)acrylate, hexanedioldi(meth)acrylate, epoxy (meth)acrylate (in particular as can besynthesized from (meth)acrylic acid and bisphenol-A diglycidyl ether,bisphenol-A diglycidyl ether oligomers, bisphenol-A or ethoxylatedbisphenol-A), trimethylol tri(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, as well asmixtures of these monomers.

The (meth)acrylate monomers used in some embodiments may have glasstransition temperatures above 55° C.

Under certain circumstances and in certain embodiments, methylmethacrylate may be selected as the (meth)acrylate monomer. For example,methyl methacrylate may be used in embodiments in which the intense odorof this monomer is not a problem. However, odorless monomers or monomerswith only a slight odor may also be used in exemplary embodiments.

The first component of the two-component (meth)acrylate adhesive ofembodiments may include at least one monomer selected from the groupincluding isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate,diethylene glycol di(meth)acrylate, epoxy (meth)acrylate (in particularas can be synthesized from (meth)acrylic acid and bisphenol-A diglycidylether, bisphenol-A diglycidyl ether oligomers, bisphenol-A orethoxylated bisphenol-A), trimethylol tri(meth)acrylate, as well asmixtures thereof.

Methacrylates are particularly useful as monomers of the first componentof embodiments.

In embodiments, the second component of the two-component (meth)acrylateadhesive may include at least one radical initiator. All radicalinitiators known to the person skilled in the art in the field of(meth)acrylate adhesives are suitable as the radical initiator. Boththermal and photochemical radical initiators can be used. In particularembodiments, the radical initiator is a peroxide, including organicperoxides such as benzoyl peroxide.

Two-component (meth)acrylate adhesives of the SikaFast® series(commercially available from Sika Schweiz AG, Zürich) and thosedisclosed in WO 02/070620, which is incorporated herein by reference inits entirety, may be particularly suitable for use in certainembodiments.

In addition a photochemically cured one-component (meth)acrylateadhesive may be used as the adhesive of embodiments, instead of atwo-component (meth)acrylate adhesive. Photochemical curing is achievedby exposure to a light source, in particular a high-pressure mercurylamp or a laser. However, such embodiments require a light source forcuring, and this may be undesirable for certain embodiments in which theadhesive area may be shaded.

In embodiments in which the adhesive is a two-component polyurethaneadhesive, the first component of the adhesive may include at least onepolyol or one polyamine and the second component may include at leastone polyisocyanate.

A polyamine is a molecule with two or more amine functional groups, suchas primary amine groups. Examples of polyamines that may be suitable foruse in embodiments are aliphatic polyamines such as ethylenediamine,1,2- and 1,3-propane-diamine, 2-methyl-1,2-propanediamine,2,2-dimethyl-1,3-propanediamine, 1,3- and 1,4-butanediamine, 1,3- and1,5-pentanediamine, 1,6-hexanediamine, 2,2,4- and2,4,4-trimethyl-hexamethylenediamine and mixtures thereof,1,7-heptanediamine, 1,8-octanediamine, 4-Aminomethyl-1,8-octanediamine,1,9-nonanediamine, 1,10-decanediamine, 1,11-undecane-diamine,1,12-dodecanediamine, methyl bis(3-aminopropyl)amine,1,5-diamino-2-methyl-pentane (MPMD), 1,3-diaminopentane (DAMP),2,5-dimethyl-1,6-hexamethylenediamine, cycloaliphatic polyamines such as1,3- and 1,4-diaminocyclohexane, bis(4-aminocyclohexyl) methane,bis-(4-amino-3-methylcyclohexyl)methane,bis(4-amino-3-ethylcyclohexyl)methane,bis(4-amino-3,5-dimethylcyclohexyl)methane,1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(=isophoronediamine orIPDA), 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, 1,3-and 1,4-bis(aminomethyl)cyclohexane, 1-cyclohexylamino-3-aminopropane,2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane (NBDA, manufactured byMitsui Chemicals),3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0^(2,6)]decane,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3- and1,4-xylylenediamine, ether group-containing aliphatic polyamines such asbis(2-aminoethyl) ether, 4,7-dioxadecane-1,10-diamine,4,9-dioxadodecane-1,12-diamine and higher oligomers thereof,polyoxyalkylene polyamines with theoretically two or three amino groups,for example as can be obtained under the name Jeffamine® (manufacturedby Huntsman Chemicals), aromatic amines such as, for example,3,5-diethyl-2,4(2,6)-diaminotoluene (Lonzacure DETDA®),3,5-dimethylthiotoluylenediamine (Ethacure 300®),4,4′-methylene-bis(2,6-diethylaniline) (MDEA),4,4′-methylene-bis(3-chloro-2,6-diethylaniline) (MCDEA), as well asmixtures of the aforementioned polyamines.

A polyol is a molecule with two or more hydroxy functional groups. Forexample, the following commercially available polyols or any mixturesthereof can be used in exemplary embodiments:

-polyoxyalkylene polyols, also called polyether polyols, which are thepolymerization product of ethylene oxide, 1,2-propylene oxide, 1,2- or2,3-butylene oxide, tetrahydrofuran or mixtures thereof, optionallypolymerized using an initiator molecule with two or three active H atomssuch as, for example, water or compounds with two or three OH groupsand/or NH₂ groups. Polyoxyalkylene polyols that may be used inembodiments include those having a low degree of unsaturation (measuredaccording to ASTM D-2849-69 and expressed in milliequivalents ofunsaturation per gram polyol (meq/g)), synthesized for example using“double metal cyanide complex catalysts” (DMC catalysts for short), aswell as polyoxyalkylene polyols with a higher degree of unsaturation,synthesized for example using anionic catalysts such as NaOH, KOH, oralkali metal alkoxides. Polyoxyalkylene diols and triols that may beparticularly suitable for some embodiments are those that have a degreeof unsaturation below 0.02 meq/g and a molecular weight in the rangefrom 1000 to 30 000 g/mol, polyoxypropylene diols and triols with amolecular weight from 400 to 8000 g/mol, as well as “EO-endcapped”(ethylene oxide-endcapped) polyoxypropylene diols or triols. The latterare special polyoxypropylene polyoxyethylene polyols, that can beobtained, for example, by alkoxylating pure polyoxypropylene polyolswith ethylene oxide, after completion of polypropoxylation, and thushave primary hydroxyl groups. Herein, the term “molecular weight” refersto the average molecular weight M_(w).

-polyhydroxy-terminated polybutadiene polyols;

-polyester polyols, synthesized for example from dihydric or trihydricalcohols such as, for example, 1,2-ethanediol, diethylene glycol,1,2-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol,1,6-hexanediol, neopentyl glycol, glycerol, 1,1,1-trimethylolpropane ormixtures of the aforementioned alcohols, with organic dicarboxylic acidsor their anhydrides or esters such as, for example, succinic acid,glutaric acid, adipic acid, suberic acid, sebacic acid,dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid,isophthalic acid, terephthalic acid, and hexahydrophthalic acid ormixtures of the aforementioned acids, as well as polyester polyolsderived from lactones such as, for example, ε-caprolactone;

-polyether polyols or polyester polyols synthesized from tetrahydric orpolyhydric alcohols such as pentaerythritol, sorbitol, mannitol, andother sugar-based alcohols.

-polycarbonate polyols, as can be obtained, for example, by reaction ofthe above-indicated alcohols (used to synthesize the polyester polyols)with dialkyl carbonates, diaryl carbonates, or phosgene.

In embodiments, the above-indicated polyols may have an averagemolecular weight from 250 to 30 000 g/mol and an average number of OHfunctional groups in the range from 1.6 to 3.

In addition to the above-indicated polyols, the following can be used asthe first component of embodiments: low molecular weight compounds withtwo or more hydroxyl groups such as, for example, 1,2-ethanediol, 1,2-and 1,3-propanediol, neopentyl glycol, diethylene glycol, triethyleneglycol, the isomeric dipropylene glycols and tripropylene glycols, theisomeric butanediols, pentanediols, hexanediols, heptanediols,octanediols, nonanediols, decanediols, and undecanediols, 1,3- and1,4-cyclohexanedimethanol, hydrogenated bisphenol-A,1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol and sugaralcohols and other alcohols with a high number of OH groups.

A polyisocyanate is a molecule with two or more isocyanate groups. Inembodiments, the second component of the adhesive may be a polyurethaneprepolymer that can be synthesized from polyisocyanates, in particularselected from the group including 1,6-hexamethylene diisocyanate (HDI),2,4- and 2,6-toluylene diisocyanate (TDI), 4,4′-diphenylmethanediisocyanate (MDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (=isophoronediisocyanate or IPDI), their isomers, their polymers, as well as theirmixtures, and polyols, including those polyols set forth above, such aspolyoxyalkylene polyols.

Two-component polyurethane adhesives of the SikaForce® series(commercially available from Sika Schweiz AG, Zürich) may be especiallysuitable for use in embodiments.

The early strength (at least until achievement of early strength highenough to permit transport of the composite abrasive body) of atwo-component polyurethane or (meth)acrylate adhesive at roomtemperature may be achieved, in some embodiments, within less than 30minutes, such as within less than 10 minutes, as measured from the timethe two components are mixed. In specific embodiments, an early strengthachieved within less than 5 minutes may be achieved.

Two-component polyurethane or (meth)acrylate adhesives of embodimentsadditionally may provide potlifes at room temperature of less than 20minutes, in particular embodiments, of less than 10 minutes. In specificembodiments, a potlife of less than 5 minutes may be obtained.

Two-component (meth)acrylate adhesives are used as the adhesives ofcertain embodiments, because this type of adhesive provides extremelyfavorable curing behavior. As a result of the radical polymerizationmechanism, the viscosity of the adhesive may abruptly increaseconsiderably only at the very end of the open time, so the adhesive canbe easily worked to practically the same extent throughout the timebetween mixing and this rise in viscosity at the end of the open time.This is not the case for addition polymerization, as occurs fortwo-component polyurethane adhesives, which may be used in otherembodiments. In embodiments in which the adhesive is a two-componentpolyurethane adhesive, the viscosity rises steadily after mixing, so thehandling properties change considerably even before the end of thepotlife. (Meth)acrylate adhesives are likewise advantageously used insome embodiments, because they reach final strength faster.

In embodiments, the two-component (meth)acrylate or polyurethaneadhesive may display thixotropic behavior. Such thixotropic propertiescan be induced chemically or physically. In embodiments, the adhesivemay have a pasty consistency. Thixotropy or a pasty consistency isespecially advantageous for some embodiments because the effect is thatan abrasive product inserted into the adhesive is held in this positionat least long enough for the adhesive to become sufficiently crosslinkedthat the adhesive has enough strength to hold the abrasive product inposition. Thixotropy is especially useful in certain embodiments,because the thixotropic behavior allows the abrasive product to beeasily inserted into the adhesive and held in position, without its ownweight making the abrasive product tip over in an uncontrolled manner.

A two-component (meth)acrylate or polyurethane adhesive can also, asneeded in embodiments, contain other components such as fillers, dryingagents, catalysts, thixotropic agents, additives such as adhesionpromoters, light stabilizers, defoamers, flow-control agents, and impactstrength modifiers. Persons skilled in the art will use their expertisein using such additives, and will use them respectively in one or bothcomponents.

FIG. 2 depicts an abrasive flap disc 9, which represents one embodimentof a composite abrasive body. Here, the abrasive products 2 areflap-shaped abrasive members that are disposed on abrasive productsupport 1, partially overlapping each other in a fan-like manner, andare bonded to abrasive product support 1 by means of a two-component(meth)acrylate or polyurethane adhesive.

This structure also can be described as a shingle-like arrangement ofabrasive flaps. Abrasive product support 1 here has the shape of acircular disc. The disc preferably has a hole 5 in the center, throughwhich a mandrel 7 can be inserted. Abrasive product support 1 alsopreferably has a reinforcing ring 6.

FIG. 3 depicts a partial cross section along line AA of FIG. 2, throughthe peripheral area of abrasive flap disc 9, and shows abrasive products2, partially overlapping in a shingle-like fashion, with abrasiveparticles 3 on their surfaces. The abrasive products are joined toabrasive product support 1 with polyurethane or (meth)acrylate adhesive4.

Finally, FIG. 4 depicts a view of a grinding machine 8 with abrasiveflap disc 9 connected by means of mandrel 7, which is inserted throughhole 5. The abrasive flap disc has abrasive products 2 radially bondedto disc-shaped abrasive product support 1.

FIG. 5 depicts an abrasive flap wheel 12, which represents anotherembodiment of a composite abrasive body. Here, the abrasive products 2are flap-shaped abrasive members disposed on abrasive product support 1,partially overlapping each other, and are bonded to abrasive productsupport 1 by means of a two-component (meth)acrylate or polyurethaneadhesive 4. Abrasive products 2 in this embodiment are on the peripheralsurface of the abrasive flap wheel. The abrasive flap wheel may have ahole at the centerline point and optionally a nut 10 with thread 11 onthe inside of the nut. The abrasive flap wheel also may have areinforcing ring 6.

FIG. 6 depicts a partial cross section along line BB of FIG. 5, throughthe peripheral area of abrasive flap wheel 12, and shows abrasiveproducts 2, partially overlapping in a shingle-like fashion, withabrasive particles 3 on their surfaces. The abrasive products are joinedto abrasive product support 1 with a polyurethane or (meth)acrylateadhesive 4.

FIG. 7 depicts a schematic view of a grinder 13 with an abrasive flapwheel 12.

Another embodiment of a composite abrasive body is an arrangement inwhich the abrasive product support is a wheel and abrasive products,such as flap-shaped abrasive products that stick out radially on theperipheral surface of the wheel in the vertical direction relative tothe peripheral surface, are bonded with a two-component polyurethane or(meth)acrylate adhesive.

Another embodiment of a composite abrasive body is an abrasive belt.Here, the abrasive product is bonded flat against am abrasive productsupport using two-component polyurethane or (meth)acrylate adhesive. Theabrasive belt can be a sheet or an endless belt.

The present disclosure also includes embodiments directed to methods forfabrication of a composite abrasive body.

The method of embodiments includes at least the steps described below.The two components of a two-component polyurethane or (meth)acrylateadhesive are mixed with each other. This operation may be carried outwith conventional mixing devices, in particular by means of a staticmixer. Then, the mixed adhesive may be applied to the abrasive productsupport, such as in the form of an adhesive bead. This operation may bedone where the abrasive products are to be joined to the abrasiveproduct support, for example in the peripheral areas of a disc or awheel. Then, the mixed adhesive is brought into contact with at leastone abrasive product before the potlife of the adhesive has elapsed.

This contact should, in embodiments be made in such a way that theabrasive product, which may be a flap-shaped abrasive member, may beinserted into the mixed uncured adhesive, which is applied to theabrasive product support, essentially vertically with respect to theabrasive product support surface, so that part of the surface is coveredby adhesive. Such an arrangement is depicted schematically in FIG. 8 a.Finally, the adhesive is cured.

One more step, involving tilting the abrasive products, may be performedbetween bringing the abrasive products into contact with the mixedadhesive and curing the adhesive. In such embodiments, the abrasiveproducts, inserted next to each other in the uncured adhesive, may betaken from an essentially vertical orientation to a tilted orientationin a controlled manner. Thus, a fan-like or shingle-like partialoverlapping of abrasive products is achieved, as shown schematically inFIG. 8. This is achieved, in particular embodiments, by means of atangential force that may be exerted on the abrasive products on theside opposite the adhesive, as is shown schematically in FIG. 8 a.

The abrasive products of some embodiments may be tilted only after allthe abrasive products have been brought into contact with the adhesive.

In the case of fabrication of an abrasive flap disc 9, this tilting ofthe flap-shaped abrasive members is may be achieved by means of acombination rotational and pushing motion of a body touching the freeedge of the upright flap-shaped abrasive members.

In some embodiments, it may be advantageous for the surface of theabrasive product support and/or the abrasive product to undergo chemicalor physical pretreatment before bonding. Such pretreatment may involve,for example, grinding, brushing, sand blasting, treatment with cleaningagents, adhesion promoter solutions, or primers. Such treatments may,for example, result in better adhesion and thus lead to greater safetyand/or load bearing capacity of the abrasive composite.

The steps of mixing, application, bringing into contact, and curingtypically are carried out at a temperature between 10° C. and 180° C.,such as between 20° C. and 80° C., or between 20° C. and 40° C. This isdone at room temperature in some embodiments.

The above-described embodiment of the method may be especially useful ifthe adhesive used exhibits thixotropic behavior and/or has a pastyconsistency.

1. A method of fabricating a composite abrasive body comprising: bondingthe abrasive support and the abrasive product together with atwo-component (meth)acrylate adhesive, wherein the two component(meth)acrylate adhesive consists of a first component which contains atleast one (meth)acrylate monomer, and a second component, which containsat least one radical initiator.
 2. The method according to claim 1,wherein the (meth)acrylate monomer is selected from the group consistingof isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate,diethylene glycol di(meth)acrylate, epoxy (meth)acrylate, trimethyloltri(meth)acrylate, and mixtures thereof.
 3. The method according toclaim 2, wherein the (meth)acrylate monomer is an epoxy (meth)acrylatesynthesized from (meth)acrylic acid and a compound selected from thegroup consisting of bisphenol-A diglycidyl ether, bisphenol-A diglycidylether oligomers, bisphenol-A and ethoxylated bisphenol-A.
 4. The methodaccording to claim 1, wherein the radical initiator is an organicperoxide.
 5. The method according to claim 1, wherein the radicalinitiator is benzoyl peroxide.
 6. The method according to claim 1,wherein the adhesive has a pasty consistency.
 7. A method of fabricatinga composite abrasive body comprising: bonding the abrasive support andthe abrasive product together with a two-component polyurethaneadhesive, wherein the two-component polyurethane adhesive consists of afirst component, which contains at least one polyamine or one polyol,and a second component, which contains at least one polyisocyanate. 8.The method according to claim 7, wherein the polyisocyanate is selectedfrom polyurethane prepolymers.
 9. The method according to claim 8,wherein the polyurethane prepolymers are synthesized frompolyisocyanates and polyols.
 10. The method of fabricating the compositeabrasive body according to claim 7, wherein the polyisocyanate isselected from the group consisting 1,6-hexamethylene diisocyanate (HDI),2,4- and 2,6-toluylene diisocyanate (TDI), 4,4′-diphenylmethanediisocyanate (MDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, isomersthereof, mixtures thereof.
 11. The method according to claim 9, whereinthe polyol is chosen from the group consisting of polyoxyalkylenepolyols.
 12. The method according to claim 7, wherein the adhesive has apasty consistency.
 13. A method of fabricating of a composite abrasivebody comprising: mixing the two components of a two-componentpolyurethane or (meth)acrylate adhesive; applying the mixed adhesive tothe abrasive product support; contacting the mixed adhesive and at leastone abrasive product; curing the adhesive.
 14. The method according toclaim 13, wherein the mixing, application, contacting, and curing stepsare carried out at a temperature between 10° C. and 180° C.
 15. Themethod according to claim 13, wherein the mixing, application,contacting, and curing steps are carried out at a temperature between20° C. and 80° C.
 16. The method according to claim 13, wherein themixing, application, contacting, and curing steps are carried out at atemperature between 20° C. and 40° C.
 17. The method according to claim13, wherein the mixing, application, contacting, and curing steps arecarried out at room temperature.
 18. The method according to claim 13,wherein a surface of the abrasive product support or a surface of theabrasive product undergo chemical or physical pretreatment beforebonding.
 19. The method according to claim 13, wherein the abrasiveproduct is a flap-shaped abrasive member and the flap-shaped abrasivemember is inserted into the mixed abrasive and applied to the abrasiveproduct support in an essentially vertical orientation with respect tothe abrasive product support surface, so that part of the surface of theflap-shaped abrasive member is covered by adhesive.
 20. The methodaccording to claim 19, wherein a plurality of flap-shaped abrasivemembers are inserted next to each other into uncured adhesive and thenare taken from an essentially vertical orientation to a tiltedorientation.
 21. The method according to claim 20, wherein theflap-shaped abrasive members overlap in a fan-like or shingle-likefashion.